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June 26, 1923.

F C. HANKER AUTOMATIC SUBSTATION Filed April 9 1918 INVENTOR fie/927k C flan/fer BY ATTORNEY Ampere:

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WITNESSES al WM Patented June 26, 1923.

UNITED STATES PATENT OFFICE.

FREDERIC HANKER, OF WILKINSBURG,

Application filed April 9,

To all whom it may concern:

Be it known that I, FREDERIC C. HANKER, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Automatic Substations, of 'which the following is a specification.

My invention relates to electrical systems and particularly to such systems in which a converter, or other similar device, is adapted to be automatically started and controlled for the purpose of supplying energy to a circuit,'under predetermined conditions.

One object of my invention is to provide means for precluding the automatic starting of a rotary converter, under predetermined conditions.

Another objectof my invention is to-pro- 'vide a generator having a drooping voltage characteristic for so impressing a voltage on theasystem that the converter will not "be started. under ,aafalse' condition of load on the circuit. '1 L A further object of'my invention is to provide at-system of the above-indicated character that shall be simple and inexpensive to construct and effective in its tion.

II-Ieretofore, the converters of substations have been provided with voltage-responsive relaysfor starting the same when the voltage on the load circuit dropped by reason of an increased load thereon. However, when all 10f the converters of such a systemare disconnected and no load obtains on the load circuit no voltage is supplied thereto and the relays will operate to start the converters. I

In view of the above, I provide a-relatively small-capacity generator having a drooping voltage characteristicand which is permanently connected to the load circuit. By the use of such a device, normal volta e is maintained on the load circuit to preclude the relays operating under false conditions of excess load, and the voltage characteristic of the generator is such that, when current is taken therefrom, its voltage rapidly decreases to permit the relays to respond to the true load condition in the circuit.

Figure 1 of the accompanying drawings is a diagrammatic view of an electrical system embodying my invention, and Fig. 2 is a diagram illustrating the voltage character- 'opera- PENNSYLVANIA, ASSIGNOR TO WESTING- COMPANY, A CORPORATION OF PENNSYL- SUBSTATION.

1918. Serial No. 227,431.

and stopped in accordance with predeterQ, c5

m i ned load and voltage conditions in the direct-current circuit 2. f If the converter 3 is located a relatively great distance from the source of alternating current, it is desirable that the starting and stopping ofthe converter be accomplished by automatic means and, in so doing, of the substation will be relatively small That is, 'ifthe converter 3 be caused to op the cost of operation.

embodying my invengij electrical system, embodying my 111:

erate only when a predetermined load is connected to thedirect-c'urrent circuit, it' will be understood the only losses in the substation will obtain when the converter is supplying energy.

The conductors of the circuit 1 are operatively connected, through a circuit interrupter 4, to the terminals of ,the primary windinjgfifof a transformer 6, the secondary winding 7 of whichis circuit interrupter 8, to 9 of the converter 3. The direct-current e'nd circuit interrupter 10, to the circuit A1 voltage-responsive relay 11 is operaconnected, through a the collector'brushes Q of the converter 3"is connected, through a tively connectedfaicross the circuit 2, and is adapted to control a circuit 12' comprising the actuating winding 13 of the circuit interrupter 8 and the actuating winding 14 of the circuit interrupter 4.

A motor-generator set 15, comprising an alternating-current motor 16 and a directcurrent generator 17, is connected, through a transformer 18, between the circuits 1 and 2, substantially as shown in the drawing. The generator 17 is adapted to have a drooping voltage characteristic, substantially as shown in the diagram of Fig. 2, and is provided for the purpose of maintaining normal: voltage on the circuit 2 under noload conditions thereon.

The relay 11 is so proportioned that, when sufficient load obtains on the circuit 2 to re duce the voltage on the; same a predetermined amount, the relay 11 will efi'ect the energization of the circuit 12 and thereby 35,. yolta e characteristic of the wally-maintaining the voltage of the directstart the converter 3 and suppiycnergy. to the circuit 2 from the circuit 1. Thus, in' electrical railway systems, when a car advances to a position, with respect to the cir 5 unit 2, that is within the sphere of operation of the converter 3, the same is started to supply the circuit 2 with energy. it will be understood that the circuit interrupter 8 is shown connected to the highpotential taps 10 of the transformer winding 7 to simplify the description of theapparatns and that, in :ictii'al'prabtice, interlocked circuit interrupters may be used for supplying the converter 3 withcurrent first at low potential and their athigh otential, substantially as set forth in copen mgapplication Serial N70; 122,377, filed September 27, 1916, by F. C. Hankerand M". Moss and assigned to the \Vestinghouse Electric and Manufacturing Com.

If the motor-generator set 15 were not provided, the relay 11 would be actuated to start the converter 3 upon, em0va1...q; all load, from the circuit 2 and failure of- 25, voltage therein. It-will be seenthat this condition will obtain under ,certain conditioz" ot operation o f-a railway system, such, for; example, as obtain .when the-sys tem is shutdown during the night hours.

In' or derfto preclude the starting of the cou t verter under siich italseload, conditions, the eiierator 1'? is adapted-to supply just sufcie nt voltage to the circuit 2 to. ,prevent the operation of the relay 11. Howeyer, -the enerator, l'I is suchhat, when current is, titan therefrom' itswol ta e rapidly decreases and thus, whena 1 5 e n t cuit-,2, ,w ial i'a sufficient Myuinvention-isnot limited torthe particular startingand controllingsystem or to 1' the motor-generator set illustrated, as it may be. variously; modified without departing i-- from' .;the-spirit and scope of the invention 1 as set ;forth in the appended claims::-:-- 1 1-;

Iiclaim,as-my'inventionri 1. In an electrical system, the co'mbinationt with analternating-current circuit, a-di-rectfibrcurrent? circuit, a converter and voltage-i,

responsive means for controlling-the'con nection of the converter between-both circuits in response to the voltage condition of the direct-current circuit, of means for norcurrent; circuit while there is no load thereon and for someducing the voltage of the directcurrent circuit, when load is placed thereon, that the voltageu-csponsive means will be caused to effect the connection of the converter between the two circuits- 2. In an electrical system, the combination with an alternating-current circuitfa direct-current circuit, a converter and voltage'responsive means for controlling the amounttoensure theti 40, t re ay, 11. v H

trical .conditionof the distributing circuit for controlling theaeonnection of the trans lating deviceto, thecircuits, of means for maintaining the electrical condition of the distributing circuit-normal while there is -no load connectednthereto and for; producingthe predetermined abnormal condition. when load is connected to the vdistributing circuit, that will render, the connection-controllingmeans .nectiom Q 4. The'combination supply circuit;

a'distributing circuit, a tra-nsformer, and

1 means for controlling the connection-of. the

transiormenbetwcen' the circuits when the voltageof the distribution circuit decreases operative. to effect-such con-.

below a ,predetemnined malue', of means for maintaining thevoltage oi the distributing circuitabove the opcrating' svalue of the connection-controllin connected to the: distributing circuit and for decreasihg-the- -voltage of the'circuit to an operating valueqfu the conriectioIi-control ling meansi 5. The combination with a supply circuit, a distributing. circuits '1 a transformer, and

means while no loadis means-'forcontrolling the connection of the museum between thef circuits"when the voltage of the distribution-circ it decreases below "-a predetermined v'alue, ='ofa ,geher-f atom-haying a? drooping -voltage "character- "iStiWtO -ma'Intain-jthE norms-1 voltageof'fihe distributingcii'cuW-JWhile 'hqil'oad' is hdn nected tlireto;-'and toquicklyreduce the" voltage of the circuit when load, is coniict ed thereto; 1 to cause the"'c oniiet:ti'o'n contrdi- .ling in'e'ans immediately mi p i- 6'. The

tween ofz niea'ri'sf'responsive to a predetermined clectrical condition y for controlling.

the connection, offth transformer 'hetw'eeh the connection of loadthretol 7. The co" b'ination with a supply circuit,

a load 'circuitfatransformer adapted to' 'be connected therebetween and mea'iis foi" controlling such connection when" the voltage of the load circuit decreases tof'o r below,

511' Ch condition in the distribntiii'glcifcllit' 119 B a predetermined value, of means for maintaining the distribution circuit voltage normal under certain load conditions and for so reducing the voltage of the distribution circuit under other load conditions, that the voltage-responsive means operates to control the connection of the transformer to the circuits.

8. The combination with two electric circuits and a transforming apparatus to be connected therebetween when a predetermined variable property or characteristic of one circuit changes from one predetermined range to another predetermined range, of means for maintaining the property or characteristic of such circuit Within one range under certain load conditions and within the other range under other load conditions.

9. The combination with an alternatingcurrent circuit, a direct-current circuit, a transformer adapted to be connected there between under predetermined voltage conditions in the direct-current circuit and voltage-responsive means for controlling such connection, of means responsive to the load connected to direct-current circuit for maintaining the voltage of the direct-current circuit at such value that the voltage-responsive means shall not function, under predetermined load conditions, and for so reducing thevoltage under other load conditions, that the voltage-responsive means shall function.

10. The combination with an alternatingcurrent circuit, a direct-current circuit. a transformer adapted to be connected therebetween under predetermined voltage conditions in the direct-current circuit and voltage-responsive means for controlling such connection, of an auxiliary transformer connected between both circuits to maintain the voltage of the direct-current circuit normal under predetermined load conditions and to reduce the voltage under other load conditions to effect the operation of the voltage-responsive connection-controlling means.

In testimony whereof, I have hereunto subscribed my name this 30th day of March, 1918.

FREDERIC C. HAN KER. 

